Optics
by meiflower
Summary: He is not an ethereal body. He is a man. Learn physics through fanfiction. Warrior of Light mild violence.


Disclaimer: I do not own Dissidia:FF or any related aspects, which belong to their respective owners. No money made.

Summary: He is not an ethereal body. He is a man. Learn physics through fanfiction.

Rating: K+

Warnings: Mild violence.

**[Dissidia:FF] Optics [Warrior of Light]**

_Calculate the velocity of light in air at STP (Standard Temperature and Pressure.)_

He jumped towards the ominous clouds above, wondering how quickly he would fall, wondering why it was so cold, so barren and lonely here, and wondering why there was such a heavy weight on his chest and shoulders.

Perhaps it was just the weight of this war.

He hung there, suspended by the air around him and the broken physics of this world. He looked down at the battleground below and thought that in this place he seemed to move more slowly; perhaps hindered by some unseen force?

Then his descent began and as he aimed for yet another abomination, another foot soldier of Chaos that wore his appearance, he shouted, "Let the light save you!"

_The index of refraction (n) is equal to the speed of light in a vacuum (c) divided by the velocity of light (v) in a given material. _

_n = c/v _

_1.0003 = 3x10^8/v_

_v = 299910027 m/s_

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_A beam of light in air is incident upon a piece of glass, striking the surface at an angle of 30 degrees. If the index of refraction of the glass is 1.5, what are the angles of reflection and refraction?_

He jumped to the side, away from the attacks of his enemy, and successfully dodged the blows. Examining his surroundings quickly and efficiently, he found that the most logical place to execute a counterattack was to his right, in the form of a large semi-transparent wall. He ran towards it.

The glass was clouded and milky, and upon closer inspection, it was also cracked. He noticed this and hoped, discreetly, that it would withstand the force of his jump. Holding in a breath, he charged.

He hit the vertical surface with both feet, pivoted on one and bounced off the wall, eliciting an exclamation of surprise from the enemy below him.

Jumping and turning simultaneously, he aimed his shield of light at his attacker. As he did so, he noticed two things: one, that with his peripheral vision he could see himself in the smooth surface of the wall, and two, that the way he flew at his enemy was decidedly different than the way he had approached the wall.

However, this was not the time for such thoughts. Releasing the energy stored in the shield, he looked on with determination and triumph as his enemy was embedded into a nearby pillar.

_If the light makes an angle of 30 degrees with the surface, then it makes an angle of 60 degrees with the normal line; this is the angle of incidence. By the Law of Reflection, then, the angle of reflection is also 60 degrees. _

_The index of refraction of the first material (n) multiplied by the sine of the angle of incidence (a) is equal to the index of refraction of the second material (n') multiplied by the sine of the angle of refraction (a'). _

_nsin(a) = n'sin(a')_

_1 x sin60 = 1.5 x sin(a')_

_sin(a') = 0.5774_

_a' = 35 degrees_

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_A person 1.8 meters tall stands in front of a vertical plane mirror. How close to the mirror must he be, if he is able to see his whole body? (Assume his eyes are 10 cm below the top of his head.)_

He wasn't fighting at the moment, and that moment allowed him to examine his appearance in a tall mirror mounted near a staircase in a once-was castle. The glass was cracked in some places but hung straight, perpendicular to the ground.

He looked at himself and he looked back at himself.

Blood and dirt adorned the edges of his cape. His armor was scratched and worn, but gleamed under the light of the EX force that floated near him amiably. He noticed that the mirror was tall enough to encompass his full form and rotated in place.

His armored feet made loud metallic clicks against the floor.

Lenient as to what constituted an acceptable appearance, he leaned in towards the mirror's surface to examine his face.

Eyes hooded as usual, countenance unreadable, lips pulled into a tight grimace. Stern eyebrows were covered by strands of hair and the edge of his horned helmet. He took it off and examined himself again.

And all at once, he realized that he was a man- just a man, only a man, and not some ethereal being made of light. He looked at himself, shocked beyond speech, and realized that he was human.

Human. He was human.

And in front of the mirror, inside the ruins of an old, abandoned castle, before Chaos and Cosmos and any other god who cared, and in the midst of an epic battle meant to span for all eternity, the Warrior of Light stood there and cried.

_The further you step back, the smaller the incident and reflected angles will be. But the rays will still be reflected at the same points, so the ray from the foot will still be reflected at mid-height. Therefore, the distance from the object to the mirror has no effect on the image. _

_The distance from the object to the mirror has no effect on the image._

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**[A/N] ****The study of light and the interaction of light and matter is termed optics.**

**I am a total physics geek. I have to say, my reasons for loving the subject all merge to one person- my current physics teacher, an amazing and highly intelligent woman.**

**This week our class is studying optics, and I was doing my homework when I ran into the second question. I loved it. I thought of WoL. I slapped my forehead. I forgot about homework and wrote this. **

**Anyway, credits go to wikipedia . org for some definitions, Princeton Review's AP Physics Exam workbook, and Giancoli's Physics B textbook.**

**Thank you very much for reading.**


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